System and method for connecting and aligning a compliant guide

ABSTRACT

A technique enables subsea intervention operations in which a compliant guide is deployed for connection with a subsea installation. A tool is provided to engage a lower end of the compliant guide in a manner that enables selective movement of the lower end between desired positions. For example, the tool may comprise a displacement mechanism that can be actuated to move the lower end of the compliant guide between an engaged position with the subsea installation and a remote parked position relative to the subsea installation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.12/194,586, filed on Aug. 20, 2008, and incorporated by referenceherein.

BACKGROUND

The retrieval of desired fluids, such as hydrocarbon based fluids, ispursued in subsea environments. Production and transfer of fluids fromsubsea wells relies on subsea installations, subsea flow lines and otherequipment. Additionally, preparation and servicing of the subsea wellrelies on the ability to conduct subsea intervention work.

Subsea intervention work involves numerous challenges not normally facedwhen working on land wells or offshore platforms. In many cases,intervention in subsea wells is performed from a floating platform orship by extending the borehole to a surface location by a tensionedriser. Also, compliant guides can be connected between the ship and asubsea installation so that various intervention tools can be movedthrough the compliant guide to the subsea installation and into awellbore.

Although many types of tools can be moved through the compliant guide,certain types of tools or tool strings are more easily deployed to thesubsea facility through the open water. Various procedures also arebetter performed without the compliant guide. As a result, the use ofcertain types of tools and procedures can be limited when a compliantguide is employed between the surface vessel and the subseainstallation.

SUMMARY

In general, the present invention provides a technique for subseaintervention operations in which a compliant guide, such as a spoolablecompliant guide, is deployed for connection with a subsea installation.The technique utilizes a tool that engages a lower end of the compliantguide to enable selective movement of the lower end between desiredpositions. For example, the tool may comprise a displacement mechanismthat can be selectively actuated to move the lower end of the compliantguide between an engaged position with the subsea installation and aremote parked position relative to the subsea installation.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the invention will hereafter be described withreference to the accompanying drawings, wherein like reference numeralsdenote like elements, and:

FIG. 1 is a schematic front elevation view of a subsea interventionsystem, according to an embodiment of the present invention;

FIG. 2 is a schematic representation illustrating movement of a lowerend of a compliant guide between an engaged position and a remote parkedposition, according to an embodiment of the present invention;

FIG. 3 is a front elevation view of a tool positioning a lower end of acompliant guide with respect to a subsea installation, according to anembodiment of the present invention;

FIG. 4 is a view similar to that of FIG. 3 but showing the tool in adifferent operational position, according to an embodiment of thepresent invention;

FIG. 5 is a view similar to that of FIG. 3 but showing the tool in adifferent operational position, according to an embodiment of thepresent invention;

FIG. 6 is a view similar to that of FIG. 3 but showing the tool in adifferent operational position, according to an embodiment of thepresent invention;

FIG. 7 is a front elevation view of another example of the toolpositioning a lower end of a compliant guide with respect to a subseainstallation, according to an alternate embodiment of the presentinvention;

FIG. 8 is a view similar to that of FIG. 7 but showing the tool in adifferent operational position, according to an embodiment of thepresent invention;

FIG. 9 is a view similar to that of FIG. 7 but showing the tool in adifferent operational position, according to an embodiment of thepresent invention; and

FIG. 10 is a view similar to that of FIG. 7 but showing the tool in adifferent operational position, according to an embodiment of thepresent invention.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to providean understanding of the present invention. However, it will beunderstood by those of ordinary skill in the art that the presentinvention may be practiced without these details and that numerousvariations or modifications from the described embodiments may bepossible.

The present invention generally relates to a technique for facilitatingintervention operations with respect to subsea wells. The techniqueinvolves the use of a compliant guide deployed between a surface vesseland a subsea installation. The tool is coupled to a lower end of thecompliant guide to enable selective movement of the lower end to aplurality of positions. For example, the tool can be used to move thelower end between an engaged position with the subsea installation and aremote parked position relative to the subsea installation. When in theengaged position, access is provided to the subsea installation and awellbore beneath the subsea installation through the compliant guide.However, when in the remote parked position, direct access is providedto the subsea facility through open water without requiring movementthrough the compliant guide. The ability to move the lower end of thecompliant guide between desired positions enables a wide variety ofintervention applications and procedures.

The compliant guide may comprise a spoolable compliant guide deployed tothe subsea installation from a surface vessel or other surface facility.The tool can be mounted on or adjacent to the subsea installation forengagement with the lower end of the compliant guide. In someapplications, all or part of the tool can be mounted to the lower end ofthe compliant guide and lowered to the subsea installation with thecompliant guide.

By way of example, the tool may function as an alignment and connectiontool able to connect the compliant guide onto an upper portion of asubsea intervention package stack that forms part of the subseainstallation. In this example, the tool also is able to disengage thecompliant guide from the subsea installation and to move a lower end ofthe compliant guide to an adjacent parked position. The tool can be usedto make multiple connections and disconnections between the compliantguide and the subsea installation without having to recover subseaequipment to the surface. In one embodiment, the compliant guide isselectively connected and disconnected from a lubricator package of thesubsea installation. When the tool is used to move the lower end of thecompliant guide to the parked position, direct vertical access isprovided to the subsea intervention package stack. The direct verticalaccess enables use of a lifting apparatus, such as a vessel crane,without recovering the compliant guide to the surface. In manyapplications, the direct access facilitates various procedures, such asloading and/or recovering certain types of downhole well interventionequipment and wellbore plugs located within a lubricator.

Referring generally to FIG. 1, an intervention system 20 is illustratedaccording to an embodiment of the present invention. In this embodiment,system 20 comprises a compliant guide 22, e.g a spoolable compliantguide, and a tool 24 coupled to a lower end 25 of the compliant guide22. Compliant guide 22 is coupled between a subsea facility/installation26 and a surface vessel 28, such as an intervention vessel located at asurface 30 of the sea. Subsea installation 26 may be located on or at aseabed floor 32.

Compliant guide 22 is flexible guide that may be arranged in a varietyof curvilinear shapes extending between a surface location, e.g.intervention vessel 28, and subsea facility 26. Compliant guide 22 alsomay be constructed as a tubular member formed from a variety ofmaterials that are sufficiently flexible, including metal materials ofappropriate cross-section and composite materials.

Depending on the type or types of intervention operations conducted,system 20 may comprise a variety of components. For example, a dynamicseal assembly 34 may be deployed in the compliant guide 22 or,alternatively, in subsea installation 26. In some applications, thedynamic seal assembly 34 may be run down through compliant guide 22 withan intervention tool 38, e.g. tool string, deployed by a conveyance 40.Conveyance 40 may be a flexible, cable-type conveyance, such as awireline or slickline. However conveyance 40 also may comprise stiffermechanisms including coiled tubing and coiled rod. Either conveyance 40or another conveyance, such as a lift line, can further be used todeploy intervention tool 38 and other equipment to subsea installation26 through the open water when compliant guide 22 is moved to a remoteparked position via tool 24.

Although a variety of subsea installations 26 can be utilized dependingon the particular environment and type of intervention operation, oneexample is illustrated in FIG. 1. In this example, the subseainstallation 26 comprises a subsea wellhead 44, which may include aChristmas tree, coupled to a subsea well 46 having a wellbore 48. Theillustrated subsea installation 26 further comprises a subsea lubricator50 and a lubricating valve 52 that may be deployed directly above subseawellhead 44. Lubricating valve 52 can be used to close the wellbore 48during certain intervention operations, such as tool change outs. Ablowout preventer 54 may be positioned above lubricating valve 52 andmay comprise one or more cut-and-seal rams 56 able to cut through theinterior of the subsea installation and seal off the subsea installationduring an emergency disconnect. The subsea installation 26 also maycomprise a second blowout preventer 58 positioned above blowoutpreventer 54 and comprising one or more sealing rams 60 able to sealagainst the conveyance 40.

Many additional or alternate components can be incorporated intointervention system 20 depending on the specific interventionapplication. For example, one or more emergency disconnect devices 62can be positioned generally at an upper end of compliant guide 22 and/orat the lower end of the compliant guide. Also, the subsea facilitycomponents can be arranged in many configurations. For example, thelubricator 50 may comprise a lower lubricator package and an upperlubricator package.

In operation, the tool 24 is used to move the lower end 25 of compliantguide 22 to a plurality of positions relative to subsea installation 26.For example, the tool 24 can be used to move lower end 25 between aconnected or engaged position 64 and a parked position 66, asillustrated schematically in FIG. 2. In some embodiments, tool 24 can beprogrammed or otherwise controlled to move the lower end 25 toadditional predetermined positions. Also, the distance compliant guide22 is moved relative to subsea installation 26 can be selected accordingto the space required when intervention tools are moved down through theopen water to subsea facility 26 and according to other operationalparameters. Depending on the operational requirements, an offsetdistance 68 and/or a tool size envelope 70 can be selected to define themovement or potential movement of lower end 25 relative to subseainstallation 26. Tool 24 is constructed to perform according to theseoperational requirements.

One example of tool 24 is illustrated in FIG. 3. In this embodiment, thetool 24 is a self-contained remotely controlled structure that moveslower end 25 between parked and engaged positions. The structure of tool24 is sufficient to suitably resist forces exerted by the compliantguide 22 as a result of environmental effects, including the inherentbuoyancy load of the compliant guide. When moving the lower end 25 to anengaged position with the subsea facility, the tool 24 aligns andconnects a suitable connector 72 of the lower end 25 with, for example,a lubricator top hub 74 of subsea installation 26. A connector clamp 76can be used to secure lower end 25 to subsea installation 26 in a mannerthat contains the well pressure. A variety of connection clamps areknown and available for use in making subsea connections.

In the embodiment illustrated, tool 24 is connected between lower end 25and a mounting structure 78 of subsea installation 26. Additionally,tool 24 comprises a displacement mechanism 80 that can be selectivelyactuated to move the lower end 25. In this example, displacementmechanism 80 comprises an articulated arm 82 that can be selectivelyarticulated to move lower end 25 relative to subsea installation 26. Byway of example, articulated arm 82 may be a hydraulic mechanism operatedvia suitable hydraulic and/or other control signals sent from thesurface via control lines 84. In an alternate embodiment, hydraulicpower for operating the tool 24 can be supplied by a subsea hydraulicpower pack, such as a hydraulic power pack of the type often installedin remotely operated vehicles.

In FIG. 3, lower end 25 of compliant guide 22 is illustrated in a parkedposition that allows direct vertical access to lubricator top hub 74.However, upon receipt of appropriate control signals via, for example,control lines 84, articulated arm 82 forces lateral movement of lowerend 25, as illustrated in FIG. 4. The lateral movement is continueduntil connector 72 of lower end 25 is properly oriented over the subseafacility, e.g. over lubricator top hub 74, as illustrated in FIG. 5.Continued hydraulic input to tool 24, via articulated arm 82, causeslower end 25 to move downwardly into full engagement with the subseainstallation 26. For example, connector 72 is moved into full engagementwith the lubricator top hub 74, as illustrated in FIG. 6. In thisembodiment, articulated arm 82 is described as a hydraulic, articulatedarm that responds to hydraulic signals. However, other types ofmechanisms, e.g. solenoid driven mechanisms, also can be used to movelower end 25 relative to subsea installation 26. Regardless, thearticulated arm 82 can be actuated repeatedly to move lower end 25between engaged and parked positions.

Another example of well tool 24 is illustrated in FIG. 7. In thisembodiment, subsea installation 26 includes the lubricator/lubricatorpackage 50 in which the lubricator top hub 74 is exposed for connectionwith the lower end 25 of compliant guide 22. As illustrated, compliantguide 22 comprises a spoolable compliant guide having a connectionassembly, e.g. connector 72, positioned at lower end 25. Thedisplacement mechanism 80 of tool 24 comprises a four bar linkage 86that is driven by a hydraulic actuator 88, although other types ofactuators can be used to move the four bar linkage 86. The four barlinkage 86 is designed to control the path traversed by lower end 25 asit moves between engaged and parked positions. It should be noted thedesign is not limited to four-bar mechanisms and other multi-barmechanisms can be constructed and used to control the path traversed bylower end 25.

In the embodiment illustrated in FIG. 7, tool 24 further comprises aguide system 90 used to connect tool 24 between subsea installation 26and lower end 25. As illustrated, guide system 90 comprises a guidemember 92 mounted on subsea installation 26 and an alignment member 94,e.g. an alignment pin, coupled to lower end 25 via, for example, fourbar linkage 86. Guide member 92 may be in the form of a guide funnelsized to receive alignment member 94 and having a guide track 96. Guidetrack 96 may be in the form of an orientation helix used to rotationallyorient alignment member 94, and thus tool 24, as alignment member 94 isinserted into guide member 92. Guide member 92 and alignment member 94enable deployment of displacement mechanism 80 with compliant guide 22and also ensure the proper rotational orientation of the tool 24relative to subsea installation 26.

As lower end 25 of compliant guide 22 is lowered toward subseainstallation 26, alignment member 94 moves into position over guidemember 92, as illustrated in FIG. 7. Continued downward movement oflower end 25 forces alignment member 94 down through guide member 92,and this motion rotationally orients tool 24 with respect to subseainstallation 26 via guide track 96, as illustrated in FIG. 8. Therotational orientation also can be used to cause engagement of othercomponents, such as hydraulic actuator 88 which is positioned forengagement with a suitable mounting mechanism 98 of subsea installation26. Alignment member 94 can be latched with or otherwise connected toguide member 92 to secure tool 24 until the compliant guide 22 iswithdrawn to the surface or otherwise lifted away from the subseainstallation.

Once alignment member 94 is engaged with guide member 92, four barlinkage 86 can be actuated via hydraulic actuator 88, as illustrated inFIG. 9. The hydraulic actuator 88 and four bar linkage 86 cooperate tomove lower end 25 along a desired path into position over subseainstallation 26, e.g. over lubricator top hub 74. Continued actuation ofthe four bar linkage causes lower end 25 to move downwardly into fullengagement with the subsea installation 26, as illustrated in FIG. 10.The hydraulic actuator 88 can be used repeatedly in cooperation with thefour bar linkage 86 to move the lower end 25 between an engagedposition, as illustrated in FIG. 10, and a parked position, such as theposition illustrated in FIG. 8.

Intervention system 20 is useful in many types of environments tofacilitate a wide variety of intervention operations. Tool 24 enables anoperator to avoid recovery of the compliant guide in a manner thatgreatly improves operational efficiency by saving time and reducing wearon the equipment. Furthermore, tool 24 can be formed from a variety ofmechanical components, and various types of actuators can be used toactuate the tool as desired for a given environment and/or interventionprocedure. The tool 24 also can be designed to move lower end 25relative to the subsea installation 26 along a variety of paths and overa variety of offset distances.

Although only a few embodiments of the present invention have beendescribed in detail above, those of ordinary skill in the art willreadily appreciate that many modifications are possible withoutmaterially departing from the teachings of this invention. Accordingly,such modifications are intended to be included within the scope of thisinvention as defined in the claims.

1. A system for use in a subsea intervention operation, comprising: asubsea installation; a compliant guide; and a tool coupled between thesubsea installation and the compliant guide, the tool further comprisinga displacement mechanism including one of (i) an articulated arm that isactuatable to separately apply both vertically and horizontally directedforces on a lower end of said compliant guide to selectively raise,lower and laterally shift the compliant guide between an engagedposition and a remote parked position relative to the subseainstallation, and (ii) a four bar linkage that is actuatable to applyboth vertically and horizontally directed forces on a lower end of saidcompliant guide to selectively raise, lower and laterally shift thecompliant guide between an engaged position and a remote parked positionrelative to the subsea installation.
 2. The system as recited in claim1, wherein the compliant guide comprises a spoolable compliant guide. 3.The system as recited in claim 2, wherein the subsea installationcomprises a lubricator package, a lower end of the spoolable compliantguide being engaged with the lubricator package when in the engagedposition.
 4. The system as recited in claim 2, wherein the spoolablecompliant guide extends down to the subsea installation from a surfacevessel.
 5. The system as recited in claim 2, wherein the displacementmechanism comprises the articulated arm being of two pieces and coupledbetween a lower end of the spoolable compliant guide and the subseainstallation capable of separately applying both vertically andhorizontally directed forces on said lower end of said compliant guide.6. The system as recited in claim 2, wherein the displacement mechanismcomprises the four bar linkage coupled between a lower end of thespoolable compliant guide and the subsea installation capable ofapplying both vertically and horizontally directed forces on said lowerend of said compliant guide.
 7. The system as recited in claim 2,wherein the tool further comprises a guide member mounted on the subseainstallation and an alignment member coupled to the spoolable compliantguide, the guide member being positioned to engage the alignment memberwhen the spoolable compliant guide is initially lowered to the subseainstallation.
 8. The system as recited in claim 7, wherein the guidemember rotationally orients the spoolable compliant guide with respectto the subsea installation.
 9. The system as recited in claim 8, whereinthe guide member comprises a guide funnel and the alignment membercomprises an alignment pin sized for receipt in the guide member. 10.The system as recited in claim 6, wherein the tool further comprises ahydraulic actuator to selectively move the four bar linkage.
 11. Amethod for facilitating an intervention operation, comprising: couplinga tool between a lower end of a compliant guide and a subseainstallation capable of one of (i) separately applying via anarticulated arm both vertically and horizontally directed forces on saidlower end of said compliant guide, and (ii) applying via a four barlinkage mechanism both vertically and horizontally directed forces onsaid lower end of said compliant guide; and operating the tool to raise,lower and shift the lower end relative to the subsea installationbetween an engaged position and a remote parked position.
 12. The methodas recited in claim 11, further comprising delivering an interventiontool through the compliant guide and through the subsea installation toa wellbore while the tool is in the engaged position.
 13. The method asrecited in claim 11, further comprising delivering an intervention toolthrough open water and into the subsea facility while the tool is in theremote parked position.
 14. The method as recited in claim 11, whereincoupling comprises coupling the tool, between the lower end of thecompliant guide and the subsea installation.
 15. The method as recitedin claim 11, wherein coupling comprises coupling the tool between thelower end of the compliant guide and a lubricator of the subseainstallation.
 16. The method as recited in claim 11, wherein operatingthe tool comprises operating the articulated arm.
 17. The method asrecited in claim 11, wherein operating the tool comprises operating thefour bar linkage mechanism.
 18. The method as recited in claim 11,wherein operating comprises utilizing hydraulics to operate the tool.19. The method as recited in claim 11, further comprising utilizing aguide member to orient the tool when the tool is delivered to the subseainstallation via the compliant guide.
 20. A method, comprising: mountinga tool at a subsea installation capable of one of (i) separatelyapplying via an articulated arm both vertically and horizontallydirected forces on said lower end of said compliant guide, and (ii)applying via a four bar linkage both vertically and horizontallydirected forces on said lower end of said compliant guide; and using thetool to raise, lower and shift a lower end of a compliant guide to aplurality of selected positions relative to the subsea installation. 21.The method as recited in claim 20, wherein using comprises using thetool to move the lower end of a spoolable compliant guide.
 22. Themethod as recited in claim 20, wherein using comprises using the tool tomove the lower end between an engaged position, in which an interventiontool can be delivered into the subsea installation through the compliantguide, and a remote parked position.
 23. The method as recited in claim20, wherein mounting comprises mounting the tool directly to the subseainstallation.
 24. The method as recited in claim 23, wherein mountingcomprises mounting a hydraulic actuator.
 25. The system as recited inclaim 1, wherein the displacement mechanism is actuatable to selectivelyraise, lower and shift the compliant guide between the engaged positionbeing lower than the parked position that is shifted and higher relativeto the subsea installation.
 26. The method as recited in claim 11,further comprising: operating the tool to raise, lower and shift thelower end between the engaged position being lower than the parkedposition that is shifted and higher relative to the subsea installation.27. The method as recited in claim 22, further comprising: using thetool to raise, lower and shift the lower end of the compliant guidebetween the engaged position being lower than the parked position thatis shifted and higher relative to the subsea installation.